Sound signal apparatus



Dec. 29, 1942. J. R. M cKAY SOUND SIGNAL APPARATUS Original Filed March14, 1938 4 Sheets-Sheet 1 M w a v INVENTOR. JZkn R fiat/fag W C. Km

HTTOIFNE) Dec. 29, 1942. J MacKAY 2,306,820

SOUND SIGNAL APPARATUS Original Filed March 14, 1938 4 SheetsSheet 2 INV EN TOR.

65 [76 166 fa/mfi Manfaq WM QKW Dec. 29, 1942. J, R, Ma CKAY 2,306,820

'SOUND SIGNAL APPARATUS Original Filed March 14, 19:58 4 Shets-Sheet 3 II/ IMF INVENTOR.

.fflim if. Mar/fay 252 BY WCMKMA Patented 29, 1942 Jolm R. MacKay, WestCaldwell, N. 1., assignor to Wallace & Tier-nan Products, Inc.,Bellevllle, N. 1., a corporation or New Jersey Original 1940, Serial No.329,060

11 Claims.

This invention relates to sound Si nal apparatus, and more particularlyto signalling or alarm devices of electrically operated t pe, such ashorns, and to control means for signalling apparatus of the characterstated. An'e'specially advantageous use or embodiment of the inventionis in fog horns, wherein ruggedness, power of sound, and dependabilityover long periods} of application March 14, 1938, Serial No. Divided andthis application April 11,

and without conflict between the signal current controlling and currentreversing means. 4

Other objects are to provide, relative to fog horns and like signalapparatus, generally sturdier and more reliable arrangements ofoperating and control elements.

v Other objects and advantages include those .which are hereinafterstated or apparent, or

time are important criteria. Such horns are I often used on floatingbuoys, and the require ments of a satisfactory horn for such use areparticularly severe. suitable for use on buoys, where they will besubject to continuous operation, exposure to the-elements and tofrequent submergence, and to operation at all angles due to the swingingand listing of the buoy. As buoys are frequently collided with, allparts of the horn'and program mechanism must be of such constructionthat they will not be damaged or operation aflected by any jar or bumpwhich'the buoy may receive, other than one where the horn or mechanismis actually hit and damaged in consequence. It is a common requirementofhorns so used, that they must sound from two to four blasts of All partsmust be of a type about-one second per minute, and that this operationis continuous for 24 hours-per day for each day of the year.

In general, sound signals such as fog horns have comprised an'electromagnet, an armature, a diaphragm associatedwith the armature,and make-and-break contacts operated. buzzer fashion, by the armature.

One object of the invention is to provide apparatus of the characterdescribed having satisfactory power and pitch characteristic, which isat ing means for synchronously controlling both the signalcharacteristic and a reversal of current flow through the horn contactsand associated current controlling contacts, periodically the enclosedparts, including the elements 25.

which are incidental to the invention. The nature. of the latter will beconveniently explained by reference to the following description andaccompanying drawings, which set forth, by way of example, certainpresently preferred embodiments of the invention.

In the drawings:

Fig. 1 is an elevation of a complete fog horn and control unit embodyingthe invention;

Fig. 2 is an enlarged longitudinal section of the horn and its operatingparts;

Fig. 3 is a plan of the upper end of Fig. 2;

Fig. 4 is a section on line 4-4 of Fig. 2;

Fig. 5 is a general wiring diagram; and

Figs. 6 to 8 inclusive are diagrammatic views of other modifications,including various arrangements for automatic current reversal.

As generally shown in Fig. 1, the sound signal device and its associatedcontrol instrumentalities may be conveniently combined in a single unit,comprising an open-mouthed trumpet or bell 20, bolted to a housing 2|for the'homdriving elements, the housing being in turn secured to a case22. The latter encloses an electricmotor unit 23, having associatedprogram cams and contacts as hereinafter described, and

also encloses fuses and a relay 24 for operating the horn. Certainadjustable elements of the horn proper, generally designated 25, may bedisposed within the casing 22, and the face oi the latter shown in Fig.1 may conveniently comprise a door or cover plate hinged (at 26a) toopen upon release of the toggle bolts 26, for access to For convenience-of access and adjustment the parts generally designated-23 and 24 aremounted on the inside of the door and are swung out of the casing withit. It will be understood that particularly where the apparatus is to beused at sea or ofl shore, as on a floating buoy, or where it isotherwise to be exposed to weather or moisture, the entire assembly ofcasing 22, housing 2| and the inner end 21 of bell 20, must bethoroughly water-tight. To that end, the peripheries ofdiaphragms,interposed gaskets, and other Joined elements, may be embedded inwaterproof plastic material, such as glyptol'lacquer'. A coneportions 32terminating in the same plane as the pole ii, to provide adjacent poleelements of opposite polarity, for powerful signal action; the magnetwinding 33 is conveniently disposed about the central pole member 3|, asshown. The central portion of the field core, via. the pole member 3|,is conveniently provided with a longitudinal hole or tunnel, to admit atubular shaft or connecting member 34 which is part of a the vibratingassembly hereinafter described. The hole or tunnel is conveniently linedwith a copper tube 34a, pressed in place, to, prevent displacement ofthe laminations of the member 3i and to guard against an accumulation ofrust in the hole, which might otherwise interfere with free movement ofmember 34.

The diaphragm structure of the horn advantageously comprises a pluralityof relatively thin diaphragms disposed in parallel and preferably.

arranged so that the distance between the diaphragms at the respectiveends or the entire set is of substantial extent. For example, in theconstruction shown, there are provided two groups of diaphragms 35 and36, separated by a substantial space; the inner diaphragm group 35conveniently comprises three diaphragms 35a spaced slightly apart, whilethe group 38 comprises two diaphragms 36a; likewise spaced slightlyapart. The diaphragms are peripherally retained to the housing 2| by aplurality of bolts 31, circumferentially spaced around the assembly.Thin supporting rings 38 serve to space the diaphragms within therespective groups, and the groups are separated by a cylindrical spacingmember 33, and all parts are preliminarlly retained in place by thebolts 31 and securely clamped to the housing 2| by a plurality of bolts43 spaced around and passing through a flange on the bell or trumpet 23,whereby the latter is also clamped against the diaphragm assembly andhousing 2|. It will be noted that the annular face of the bell whichabuts against the diaphragm assembly, specifically the outer diaphragmgroup 36, is provided with a relatively wide annular groove 4|, so thatthe area of contact between the hell or horn proper, and the diaphragmassembly, is confined to a pair of spaced, concentric and relativelynarrow annular paths 42 and 43, affording an extremely close fit of thebell 23 against the diaphragm assembl and the housing.

' The several diaphragms a. and 36a. are centrally piercedby-and securedto a sleeve 45,

having its interior in threaded engagement with the outside of tube 34.Intermediate the several diaphragms of each group on the sleeve 45,central spacing washers s are provided for accurately spacing thediaphragms at the center, and when the assembly is made up, the ends ofthe tube 45 are advantageously upset or riveted against the heavyterminal washers 45b, whereby each diaphragm group is firmly securedagainst its corresponding shoulder 450 on the tube 45. The oppodte endof the tube 34 on the other side of the electro-magnet 33, is seated inan armss,soo,sso

ture 43, which comprises laminations of iron or preferably steel in thesame plane as laminations of the neld core 3i, 32, and which is disposedin proximity to the poles of the latter. A long bolt 41 extends throughthe tubular shaft 34 into threaded engagement with a member 43, whichprovides an extension for the shaft 34 beyond the armature 43, and intowhich the bolt 41 may be tightened so that the head of the latterengages a lock washer 48a against a large knurled washer 49 which iskeyed to the shaft 34 and abuts the end of sleeve 48, and the sleeve islocked in adjusted position on the shaft 34. Before the bolt 41 istightened, the knurled washer 48 may be turned to screw the sleeve 34longitudinally in the sleeve 45 so as to adjust the air gap betweenarmature 46 and the core 3|. 32.

It will be understood that in the preferred construction shown, thepassage of shaft 34 through the hole in pole 3| (strictly speaking,through the tube 34a) is completely freei.e., there is no contactanywhere-and indeed the shaft is entirely clear of supporting engagementor abutment at any point above the diaphragm assembly as seen in Fig. 2.That is, the spaced groups of diaphragms 35 and 38, serve alone, andvery satisfactorily, to support the remainder of the vibrating assembly,including shaft 34 and the driving armature 46. Frictional, spring orother supplementary supports for the vibrating instrumentalities arethus entirely eliminated, and at the same time the arrangement is suchthat the respective positions of the various parts carried by orconnected to the shaft 34 may be readily adjusted and the partsaccurately locked in adjusted position. Furthermore, by virtue of theinclusion of a plurality, and preferably a multiplicity, of spacedparallel diaphragms which are each relatively thin, an eminentlydesirable stiffness is obtained for the diaphragm structure withouttendency of breakage on the part of its individual constituents. Inother words, the diaphragm arrangement may safely be stiff enough toprovide a desirably high pitch, although a relatively heavy armature 46'is used to obtain powerful driving action. For example, a horn of, thetype shown has been satisfactorily constructed to produce a note of 205to 210 cycles per second, yet strong enough to be heard clearly forseveral miles, under average listening condit ons.

The outer end of the member 48 carries one contact "a 'of' a pair ofcontacts generally designated 50, and arranged to open or close inaccordance with longitudinal displacement of the shaft 34. The othercontact 53b of the set is mounted on a spring 5|, conveniently securedto but insulated from the casing 22. To avoid flexing of its endportion, the spring 5i may have a reinforcing plate, or it maypreferably have integral upwardly turned ears 52 along its sides, whichnot only reinforce the end of the spring, but enlarge its end area so asto prevent breakage adjacent the hole where contact b is mounted. Thecontact 5012, moreover, preferably has a tubular shank 50c whereby it isriveted in the hole of the spring, so that when the contact heats up inuse, the shank may expand inwardly and avoid straining the spring ii.The outerwend of the spring 5| extends beyond the contacts and isadapted to strike an anvil member 53 which is thus arranged to limit themotion of the spring downward as seen in Fig. 2. The anvil member 53advantageously comprises a worm gear mounted on a shaft which isthreaded into a cross member 54 that is suitably insulated from thehousing 2| and case 22 .(it being understood'that the housing and caseare convenient- 1y bolted together at 55a, as shown). The lower end ofthe worm gear shaft has threaded on it a leaf spring 53a, which has itsends-abutting the under side of the member 54 and which strongly biasesthe worm gear in a downward direction to prevent play and chatter. A pin53b, carried by member 54, engages a slot in the leaf spring 53a toprevent rotation of the latter.

A'worm .55 is journaled in suitable supports on' the member 54, for.rotative engagement with the gear 53, and is provided with a milled orengages'the teeth of the wheel 56; and the arrangement is such that byinserting a screw driver in the slot of member 51, and turning the same,the worm 55 will rotate the gear 53 and raise or lower the upper oranvil face of the latter with respect to the outer end of spring 5|.During suchadjustment the check 58 clicks over the teeth of wheel 55,but serves to lock the assembly in any adjusted position. The slottedshaft or head 51 is preferably insulated from the assembly of wheel 56and worm 55, so as to prevent electric shock to the operator making.adjustments, or' inadvertent grounding should his screw driver alsotouch the metal casing. Preferably both the anvil 53 and contact spring5| are of hardened steel construction, for maximum wear resistance. Itmay now be explained that the parts generally designated 25 in Fig. 1may comprise the elements 51, 55, 53, 5| and 56, which and past itsoriginal position as shown in- Fig. 5, and the cycle is repeated. Otherthings being equal (except the current consumption) the amplitude ofdiaphragm vibration is dependent upon the space 62 intermediate theupper surface of anvil 53 and the outer end of spring 5| in its neutralor rest position; that is, the wider the space the longer the contacts50 are closed during each stroke, and the greater the force exerted onthe armature 46. It will now be seen that the described horn structure,including the worm 55 for varying the position of anvil member 53 withrespect to the spring 5|, is provided with effective means for adjustingthe amplitude of diaphragm vibration, so as to obtain and maintain thedesired amplitude at all times and without excess current consumption.

When the horn is used for marine signalling purposes, for which it isnotably adapted, it must draw a relatively substantial current in orderto produce a signal sumciently powerful to be heard, say, for severalmiles. Under such circumstances for example, where the horn is locatedand hooked up, as on a floating buoy, to operate automatically atfrequent intervals-long continued use is apt to wear down the surfacesof the rapidly operated contacts 50 (even though "a condenser 63 or acondenser-resistor unit, is

are thus readily accessible, through the door of casing 22, forinspection and adjustment. 1

It will be understood that the lower contact I also diagrammaticallyshown at the upper part of Fig.5, except that for purposes of simplicitythe diaphragm structure is shown as a single dia-' phragm member 66. Itwill here be seen that the internal wiring arrangement of the horn issimply such that the winding 33 is connected in series with the contacts56 across the input terminals 6|, the path from the contacts 56 to thelower one of the-terminals 6| being conveniently through ground asdiagrammatically indicated. Actually, in the apparatus of Figs. 1 to 4,this grounded path extends from contact 50a through the shaft 34 and thediaphragm assembly, to housing 2|.

Assume for the time being that a suitable source of current, such as astorage battery, is connected across the terminals 6|. Contacts 56 arenormally in closed position, and the winding 33 being thus energized,the armature 46 is attracted by the field poles 3| and 32. The contactsremain closed, i. e., the spring 5| follows the downward displacement ofthe armature" (Fig. 5), until the outer end of the spring strikes theanvil 53. The downward stroke of the armature and diaphragm assembly4666 then continues, as will now be well understood, and upon the returnstroke (initiated by the energy stored in the diaphragm), contacts 50again tive positions in operation.- Fig. 5 accordingly shows aparticularly advantageous arrangement for automatic intermittentoperation of the horn, and at the same time, for avoiding or greatlyreducing the wear on the contacts.

It has been explained hereinabove that the casing 22 may contain a motor23, together with an associated cycling mechanism and a'horn controllingrelay 24. As shown diagrammatically in Fig. 5, the electric motor 23,which may be energized from a pair of storage batteries and 66,connected in series, is adapted to drive a pair of cams 61 and 68.Although other motors may be satisfactorily employed in many cases, Iprefer to use a motor of the type described and claimed in United StatesPatent No. 1,985,357, to Charles F. Wallace, for Electric motorapparatus; it will be understood that where the device is expected tooperate continuously for long periods of time and without attention, itis desirable to employ a motor having the low current consumption,constant speed and general dependability characteristic of the patentedmotor.

Cam 6! is provided, for example, with two oppositely disposed rises orhigh spots 69, and a pair of normally open cam contacts 10 are arrangedto be closed by each passageof a rise 69-thus in the instance shown,twice during each revolution of cam 61. Cam 68, which may be assumedclose, and under a presently preferred adjust- 'ment with respect to thenatural period of the to rotate at the same speed as cam 61, is providedwith a single rise H, which is longer in extent than either rise 69 ofcam 61, and -which is so disposed that it shifts at contact-operatingfollower l2 shortly before contacts 10 are closed by one rise 69 of cam61, and keeps the follower in shifted position until after the same rise69 (on cam 6'!) has passed the contacts 10 and permitted them to reopen.When shifted, the follower 12 is adapted to open the normally closedcontacts 13 and to close the normallyopen contacts 14.

One of the input terminals 6| of the horn is and 66, and it will now beappreciated that, as-

suming contacts H to be closed, the horn is connected to battery 65 orbattery 06 respectively according to whether contacts 13 or 14 areclosed. Furthermore, since the sides of the batteries 65 and 66 whichare connected together through the common connection 16 are opposite insign, the current flow through the horn when contacts I3 are closed isin the reverse direction from the flow when contacts 14 are closed. Thelow-current relay 24 is conveniently used to avoid the association ofheavy duty contacts with the timing cam 61 (although in some cases,heavy duty contacts may beused at and the relay 24 omitted) and thewinding of the relay may be connected as shown, through contacts 10 tothe midpoint I6 of the batteries, and also through the contact arm 12aand selectively through contacts 13 or H, to the other side of one orthe other of the It will be appreciated, of course, that the number ofrises 63 on cam 81 and correspondingly the use of one or more rises IIon cam 68 may be varied to suit requirements of design or operation. Inone embodiment of the invention, the arrangement has been that shown inFig. 5, with the rises 89 of such length, and with the motor 23 drivingthe cam 61 at such rate (2 R. P. 101.), that the horn makes fourone-second blasts each minute; and with continuous operation of thatchar- 'acter for a period exceeding six months-four blasts per minute,day and night-there was no appreciable deformation of the contacts 50and very little appreciable wear.

It will be understood that the capacity of condenser 63 (for ease inmounting, two condensers 63 are shown in Fig. 3 and will be understoodas connected in parallel) may be readily selected to coordinate theperiod of the electrical circuit with the natural period of themechanical elements.

The arrangements shown in Figs. 6, 7 and 8 are, generally stated,modified forms of the current-reversing instrumentalities shown in Fig.5.

- Referring first to Fig. 6, the horn is generally inbatteries in thesame manner as the horn itself.

Assume now that the motor 23 is rotating the cams 61 and 68, in acounterclockwise direction, from the position shown in Fig.5. The risell of cam 68 first shifts the follower 12 so as to close contacts 'I4and open contacts 13. Thereafter one rise 69 of cam 61 causes contacts10 to close and the relay 24 is accordingly energized from battery 86.Energization of relay 20 closes its contacts 17, so that current issupplied to the horn, through its input terminals 6|, from bat tery(SS-contacts 14 being now closed. The horn continues to blow until therise 69 passes contacts 10. opening them, thereby de-energizing relay 24and opening its contacts 11 in the supply circuit to the horn.Thereafter, the follower 12 drops down from the rise 1|, and contacts 13are closed. They remain closed during the time that the other oropposite rise 69 of cam 67 closes the contacts I0; and it will now beunderstood that when the contacts 10 are thus again closed to energizethe relay 24 and operate the horn, both the relay and the horn aresupplied from battery 65, and current fiows through the horn in thereverse direction from that during the immediately previous period ofenergization. In other words, as the motor 23 continues to drive cams 61and 68, the horn is periodically sounded and the direction of currentflow through it is reversed each time, so thatwear or other disturbanceof the horn contacts 50, particularly as occasioned by transposition ofmetal between these contacts, is very greatly reduced; the action at thecontacts 50 is thus, so to speak, a series of brief tendencies to carrythe metal first one way and then back again respectively, so that over along period of time the contacts are relatively unaffected by metaltransposition.

It will be noted that the arrangement of cams 61 and 68 is such thatcontacts 13 and 14 are operated at times when no current is flowing, soas to avoid wear of these contacts by arcing. At the same time, it willbe noted thatthe program contacts 10 and the heavy duty relay contacts11 both benefit by the same reversal of current flow which is providedfor the horn; in consequence, wear or other deformation of contacts 10and TI is greatly obviated.

dicated at 200, the program cam at 20l, and the cam-driving motor at202. Although a motor of thetype specifically illustrated in WallacePatent No. 1,985,357, maybe employed,'I have indicated a form of motorshown and described in the patent of Wallace and MacKay, No. 2,181,841,granted November 2 8, 1939, for Motors and motor operated apparatus,wherein, a plurality of field windings are provided, successivelyenergized by a plurality of batteries 203 and 2". The program cam MI isadapted to operate apair of contacts 205, which, when closed, causeenergization of the winding 206 of a control and reversing relay. Thecircuit of winding 200 extends from ground, through contacts 205,conductor 208, winding 208, alternatively through contacts 209 or M0 tothe positive side of battery 203 or the negative side of battery 204,and from the common return side of the batteries back to ground.Energization of relay winding 206 causes attraction of its armature 2H,and when the same is fully attracted, effects consequent closure of aset of contacts 2l2. Closure of contacts 2l2 causes energization of thehorn 200, the circuit being from ground through the horn, contacts 2l2,alternatively through contacts 209 or 210 to the positive side ofbattery 203 or the negative side of battery 204, and from their commonreturn point back to ground.

The armature 2| I carries a spring pressed pawl 2l3, which is adapted toengage the teeth of a ratchet 2H mounted for efi'ecting rotation of areversing cam 2l5. The contacts 209 and 2| 0 are operatedby a follower2| 6, on cam 2l5, whereby the contacts are alternatively closed inaccordance with the position of the follower on a high spot or low spotof the cam. The arrangement of the pawl 2l3 and ratchet 2 I4 is suchthat upon downward displacement of the armature 2 (when it is attractedby the relay magnet 206) the pawl clicks idly past the ratchet teeth,and is pulled back by its springuntil a stop-arm 2| 8 carried by thepawl comes to rest against a pin 2|9a on the armature 2| I. By theinstrumentalities just described, the pawl is so disposed on thedownstroke of the armature, that upon a succeeding up-stroke it will notcome into operative engagement with a tooth of the ratchet wheel 2| 4until after contacts 2I2 have been opened by the release of thearmature. Further upward displacement of the armature (under theinfluence of its spring 2l9 about a pivot 220) causes the pawl 2| 3 toengage the ratchet wheel 2M and rotate it, with its cam 21 5, in acounter-clockwise direction as seen in Fig. 6.

It may be explained that the arrangement of the pawl and ratchet isconveniently such that for each upward displacement of the armature theratchet wheel and cam are rotated sufficiently for the follower 2H5 tomove from a high not to a low spot or vice versa. For example, if thepawl is adapted to move the ratchet a distance corresponding to onetooth on each upward displacement of the armature 2| I, and if the cam2l5 is provided with, say, six high spots, the ratchet wheel should havetwelve teeth to effect the desired action.

It will now be seen that each time a high? spot of the program camcloses the contacts 205, the relay winding 206 is energized, and thecontacts 2l2 are closed to eifect operation of the horn. Upon subsequentopening of the contacts 205, the relay is de-energized, the horn isfirst turned off by the opening of the contacts M2, and thereafter theupward operation of the armature'2l lso steps or displaces the reversingcam 2I5 as to by contacts 230, it will be readily seen that thereversing switch 233 is operated intermediate all successive closures ofcontacts by cam 61, and current flows through the horn in a reversedirection each time it is sounded. For convenience of illustration inFig. 7, the circuit has not been shown so as to effect reversal ofcurrent through contacts 15, but it will be understood in view of thedescription of the preceding figures, that current reversal throughthese contacts may be easily provided. It will be further noted that, asin the case of contacts 73 and It in Fig. 5, the switch 233 is operatedat a time when no current is flowing in the circuit of the horn motor,so as to avoid wear of the contacts of this switch.

In Fig. 8 a somewhat simplified arrangement is shown, which I nowbelieve to be preferable the horn and through the winding of relay 206is reversed for each operation of the horn, the reversing contacts 209and 2H! being operated only at times when there is no flow of current,so as to avoid injury to these contacts, as explained in connection withcontacts I5 and Id of Fig. 5. Furthermore," in the arrangement of Fig. 6the reversing cam need not be specially designed for synchronism withthe program cam 20!; that is, the program cam 20! may be readilymodified or changed so as to provide any desired program of contactclosure and horn operation, without in any way having to modify thestructure of the reversing cam. It will be noted that as in the case ofcontacts '10 and ll of Fig. 5, the apparatus of Fig. 6 provides not onlya reversal of current flow through the contacts in the horn mechanism200, but also a reversal of current flow through contacts 205 and 2 l2,after each interval of horn operation.

The arrangement of Fig. 7 is in a number of respects similar to that ofFig. 5, with certain exceptions, including the provision of a separatereversing relay, arranged for operation of the system from a singlebattery or source of power.

The motor 23 rotates a program cam '51 and a reversing cam 68, as in thecase of Fig. 5, and energization of the horn 20B is controlled by thecontacts 1'! of a control relay 25, likewise similar to the relay 25 ofFig. 5. Instead of providing a set of reversing contacts mechanicallyassociated with the reversing cam '58, the arrangement of Fig. 7includes a single pair of normally open contacts 230 adapted to beclosed by the high spot of cam 58. Closure of these contacts connectsthe winding of a relay 23!, across the battery 232, to energize therelay. The contacts of this relay are arranged as a double-pole.doublethrow switch, disposed in the circuit of the horn 200 and thebattery 232, to provide for a reversal of the current through the horn,and also through the horn controlling contacts ll, each time the Iswitch is operated by energization or de-energization of the relay.Since the contacts 230 are timed by cam 58 in the same manner, withrespect to cam 51, as contacts 13 and 14 in Fig. 5, and since thereversing switch 235 is controlled in a number of respects. The programcam 255 is driven continuously by the motor 23. which may be of the typeof the Wallace patent previously mentioned, and which is energized fromthe battery 25!. A double-pole double-throw reversing switch 252 isprovided intermediate the battery 25l and the horn 200, the latter beingin series with its control contacts 253 that are closed by the highspots of the cam 250. It will thus be seen that through a groundconnection, the horn 200 and contacts 253 are connected across theshiftable elements 255 and 255 of the reversin switch 252; and dependingupon the position of the shiftable switch elements relative to theirassociated contacts, the horn is energized by a flow of current in onedirection or the other from the battery 25l, when contacts 253 areclosed.

For operation of the contacts 253 and other instrumentalities presentlyto be described, the cam 250 is Provided with a follower member 260pivoted at 26l, and biased toward the cam by a spring 252, thearrangement being such that contacts 253 are not closed until thefollower isapproximately fully lifted by a high spot of the cam, and areopened as soon as the follower starts to descend from a high spot. Thereversing switch 252 is operated by displacement of a follower 253 on areversing cam 25.5 which is incchanically connected for rotation by aratchet wheel 265. A spring-pressed pawl member 266 is pivoted to andextends upwardlyfrom the program follower member 260, and is providedwith an interior slot 26'! whereby it surrounds a group of teeth of theratchet wheel 265, and is adapted, when pulled down by member 265, torotate the ratchet wheel in a clockwise direction by engagement of theupper edge of its slot 261 with atooth of the ratchet. The arrangementis thus such that when the member 260 is moved up by a high spot of cam250, the contacts 253 are eventually closed, but the pawl 255 clicksidly by the teeth of the ratchet. On the subsequent downwarddisplacement of the member 26!), contacts 253 first open and thereafterthe pawl 256 effects a predetermined step of rotation of the ratchetwheel and cam 26% as heretofore described. The arrangement of theratchet wheel and cam 254 may conveniently be the same as that ofcorresponding parts 214 and 215, in Fig. 6, i. e., so that there is areversing action of the switch 252 each time that the pawl is operated.

It will now be seen that the structure of Fig. 8 provides a simpleand'eifective mechanically controlled arrangement for automaticallyreversing the flow of current through the horn and through its controlcontacts 253 after each interval of horn energization. Furthermore, asin the case of Fig. 6, the configuration of the program cam 250 may bevaried or changed at will to provide any desired program of hornoperation, without any modification of the reversing cam 264 or of theother instrumentalities for effecting the automatic current reversal.

The arrangement of Fig. 8 has certain advantages of economy andefiiciency over that of Fig. 6 and over other arrangements hereindescribed: for example, all of the control apparatus is operated by thesingle motor mechanism 23, which may be of the notably efficient Wallacetype (or Wallace and MacKay type) as hereinabove described, havingexceptionally economical operating characteristics. No supplementaryrelays or magnetically controlled devices are needed and the currentdrain from the battery or other power source 25l is reduced to aminimum.

It will now be appreciated that the present invention not only affords ahorn which is relatively simple in construction, dependable inoperation, and easily built, to have any predetermined pitch within awide range, but also affords distinctively improved control arrangementsfor such horns so as to avoid contact wear and impairment of normaloperation. The advantages realized by the invention are, furthermore, ofspecial importance where the signal device is to be automaticallyintermittently operated at frequent intervals and iii a location (as ona marine buoy) where it must give reliable service without frequentattention. On the one hand, the working vibration of the diaphragm andassociated driving assembly is necessarily powerful, and tends to set updisturbing vibrations in every part that is mechanically connected withthe apparatus; on the other hand, the electrical parts, notablycontacts, are subjected to driving or control operation on each of themany hundred or often several thousand separate occasions on which thesignal is operated every day. The invention is particularly effective inobviating or minimizing the wear or other derangement which wouldotherwise inevitably result from the strenuous operating conditions justdescribed.

In accordance with the provisions of the patent statutes, I have hereindescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodimentsthereof, but I desire to have it understood that th apparatus disclosedis only illustrative and that the invention can be carried out by othermeans. Also, while it is designed to use the various features andelements in the combinations and relations described, some of these maybe altered and others omitted and some of the features of eachmodification may be embodied in the others without interfering with themore general results outlined, and the invention extends to such usewithin the scope of the appended claims.

This application is a division of my copending application Serial No.195,893, filed March 14, 1938, for Sound signal apparatus.

I claim:

1. Control apparatus for an electrically operated device having a supplycircuit therefor, comprising switch means for effecting control of saidsupply circuit to operate the said device, said switch means beingoperable for successively effecting initiation and interruption ofcurrent supply in said supply circuit, said switch means havingassociated program means for repeatedly operating said switch means, forsuccessively initiating and interrupting operation of said device inaccordance with a program, means for reversing the direction of currentflow in said supply circuit, and means controlled by said switch meansand responsive to each operation thereof which interrupts current supplyin said circuit, for operating the reversing means after each time theprogram means has caused operation of the said device.

2. The combination of claim 1, in which the last-recited means compriseselectromagnetic means electrically responsive to said switch means uponoperation of the latter to interrupt current supply to the aforesaiddevice, whereby the reversing means is operated only when no current isflowing in the supply circuit.

3. The combination of claim 1, in which the switch means includes acontrol element shiftable by the program means to effect closure of thesupply circuit, and in which the means for operating the reversing meansis mechanically responsive to the return displacement of said controlelement after the supply circuit has been opened.

4. Control apparatus for an electrically operated device havingmake-and-break contacts in an energizing circuit thereof, comprisingcircuitcontrolling contact means for opening and closing said energizingcircuit at desired times, relay means for operating said contact means.a second contact means for controlling operation of the relay means,associated circuit-controlling means for intermittently reversing theflow of current through the make-and-break contacts and thecircuit-controlling contact means and the second contact means toprevent impairment of operation of said device by wear of any of saidcontact means, and program means for'operating said second contact meansand said associated circuitcontrolling means in accordance with aselected program.

5. Control apapratus for an electrically operated device, comprisingmeans to connect said device with a source of current and including aset of contacts having means displaceable to close and open saidcontacts, and means operated by contact-opening displacement of saidlast-mentioned means for reversing the polarity of the source of currentwith respect to the aforesaid device and said contacts.

6. Control apparatus for an electrical device which is to be operatedintermittently in accordance with a desired program and which has acurrent supply circuit therefor, comprising program cam means havingselected camming characteristics, follower means intermittentlydisplaced by the cam means and in accordance with the characteristicsthereof, and circuit controlling means for the supply circuit, operatedonly in response to displacements of the follower means and includingswitch means for controlling operation of the electrical device, saidcircuitcontrolling means also including reversing switch means forintermittently reversing the direction of current flow through saidelectrical device and said first-mentioned switch means, in intervalsintermediate operations of the electrical device. both said switch meansbeing controlled by the follower means and operated only in response todisplacements of said follower means and being arranged for operation intimed relation, under control of the cam means, whereby the reversingswitch means is operated only when the firstmentioned switch means isopen.

7. In combination, a circuit adapted to supply current to an electricaldevice, a program cam, a member displaceable by the cam, a switchoperable by said member upon displacement thereof in one direction forclosing said circuit, and for opening said circuit upon returndisplacement of the member, a switch connected in said circuit forreversing the direction of current flow through the electrical deviceand the first-mentioned switch, and means actuated by said member uponadisplacement thereof and timed to operate when said first-mentionedswitch is in open circuit osition, for operating said reversing switch.

8. The combination of claim '7 wherein the re- .versing switch has asingle operating member second-mentioned cam through said predetermineddistance.

9. In combination, a current supply circuit, a switch having contacts insaid circuit to be closed or opened, a control member therefor shiftablein one direction to close the contacts and in another direction to openthe contacts, a reversing switch associated with said circuit forreversing the direction of current flow therein and through saidcontacts, and means operated by said control member upon displacement ofsame in one of said directions, for operating the reversing switch.

10. Control apparatus for an electrically operated device having asupply circuit therefor, comrising switch means for opening and closingsaid supply circuit to operate said device, means ineluding aprogramcam, for operating said switch means, means for reversing thedirection of current flow in said supply circuit, means including aprogram cam, for operating said reversing means, and common drivingmeans for actuating said cams in synchronism, said second-mentioned cambeing arranged and timed relative to said first-mentioned cam, foroperating the reversing means only at predetermined times when thesupply circuit is open.

11. Control apparatus for operating, in accordance with a selectedprogram, an electrical device having make-and-break contacts rapidly andrepeatedly operated during each operation of said device, said apparatuscomprising program cam means having selected camming characteristics,follower means intermittently displaced by the cam means and inaccordance with the characteristics thereof, a current supply circuitfor supplying the electrical device, and circuit controlling means forsaid circuit operated only in response to displacements of the followermeans and including switch means for opening and closing said supplycircuit in accordance with a program determined by the cam means, saidcircuitcontrolling means also including reversing switch means operatedin response to said cam means and timed to operate only at times whenthe supply circuit is open at the first mentioned switch means, forintermittently reversing the polarity of electricalsupply in said supplycircuit, to reverse the direction of current flow through the electricaldevice. JOHN R. MacKAY.

